Directions:

1. To make the Fudge Ripple: Whisk together the sugar, corn syrup, water, and cocoa powder in a medium saucepan. Heat over medium heat, whisking constantly, until the mixture begins to bubble at the edges. Continue to whisk until it just comes to a low boil. Cook for 1 minute, whisking frequently. Remove from the heat, stir in the vanilla, and let cool. Chill in the refrigerator before using. (Fudge Ripple can be stored for up to 2 weeks, covered, in the refrigerator.)

2. To make the Peanut Butter Patties: Mix together the peanut butter and confectioners' sugar in a small bowl. Line a dinner plate with plastic wrap. Pinch off small pieces of the peanut butter mixture, about ½ teaspoon each, and drop them onto the dinner plate. Once you've used all of the mixture, freeze the patties. (The patties can be stored in the freezer, well wrapped, for up to 1 month.)

3. To make the Ice Cream: Whisk together the half-and-half, cocoa powder, granulated sugar, and salt in a large saucepan over medium heat. Heat the mixture, whisking frequently, until it comes to a full, rolling boil (it will start to foam up). Remove from the heat and whisk in the peanut butter, stirring until thoroughly blended.

4. Chill mixture thoroughly, then freeze it in your ice cream maker according to the manufacturer's directions. Fold in the Peanut Butter Patties when it has finished churning. Just before you remove the ice cream from the machine, spoon some of the Fudge Ripple onto the bottom of the storage container. As you remove the ice cream from the machine, layer generous spoonfuls of the sauce between layers of ice cream. Avoid stirring the Fudge Ripple, as it will make the ice cream muddy.